115 lines
2.5 KiB
Go
115 lines
2.5 KiB
Go
package storage
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import (
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"encoding/json"
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"errors"
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"io/fs"
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"os"
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"path/filepath"
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"git.nicholasnovak.io/nnovak/spatial-db/world"
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)
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const fileCacheSize = 8
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var (
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ChunkNotFoundError = errors.New("chunk was not found in storage")
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)
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type SimpleServer struct {
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StorageDir string
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cache FileCache
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}
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func (s *SimpleServer) SetStorageRoot(path string) {
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s.StorageDir = path
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s.cache = NewFileCache(256)
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}
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// Filesystem operations
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func (s *SimpleServer) FetchOrCreateChunk(pos world.ChunkPos) (world.ChunkData, error) {
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chunkFileName := filepath.Join(s.StorageDir, pos.ToFileName())
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var chunkData world.ChunkData
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chunkFile, err := os.Open(chunkFileName)
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if err != nil {
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if errors.Is(err, fs.ErrNotExist) {
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// There was no chunk that exists, create a blank one
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chunkFile, err = os.Create(chunkFileName)
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if err != nil {
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return chunkData, err
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}
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// Initilize the file with some blank data
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if err := json.NewEncoder(chunkFile).Encode(chunkData); err != nil {
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return chunkData, err
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}
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if _, err := chunkFile.Seek(0, 0); err != nil {
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return chunkData, err
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}
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} else {
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return chunkData, err
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}
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}
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defer chunkFile.Close()
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return ReadChunkFromFile(chunkFile)
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}
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// `FetchChunk' fetches the chunk's data, given the chunk's position
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func (s *SimpleServer) FetchChunk(pos world.ChunkPos) (world.ChunkData, error) {
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chunkFileName := filepath.Join(s.StorageDir, pos.ToFileName())
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var chunkData world.ChunkData
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chunkFile, err := s.cache.FetchFile(chunkFileName)
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if err != nil {
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if errors.Is(err, fs.ErrNotExist) {
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return chunkData, ChunkNotFoundError
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} else {
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return chunkData, err
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}
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}
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return ReadChunkFromFile(chunkFile)
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}
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// Voxel server implementation
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func (s *SimpleServer) ChangeBlock(
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worldPosition world.BlockPos,
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targetState world.BlockID,
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) error {
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chunk, err := s.FetchOrCreateChunk(worldPosition.ToChunkPos())
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if err != nil {
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return err
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}
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chunk.SectionFor(worldPosition).UpdateBlock(worldPosition, targetState)
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return nil
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}
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func (s *SimpleServer) ChangeBlockRange(
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targetState world.BlockID,
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start, end world.BlockPos,
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) error {
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panic("ChangeBlockRange is unimplemented")
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}
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func (s *SimpleServer) ReadBlockAt(pos world.BlockPos) (world.BlockID, error) {
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chunk, err := s.FetchChunk(pos.ToChunkPos())
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if err != nil {
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return world.Empty, err
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}
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return chunk.SectionFor(pos).FetchBlock(pos), nil
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}
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func (s *SimpleServer) ReadChunkAt(pos world.ChunkPos) (world.ChunkData, error) {
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return s.FetchOrCreateChunk(pos)
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}
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